Impact
CarrierWave::Uploader::ContentTypeAllowlist has a Content-Type allowlist bypass vulnerability, possibly leading to XSS.
The validation in allowlisted_content_type? determines Content-Type permissions by performing a partial match.
If the content_type argument of allowlisted_content_type? is passed a value crafted by the attacker, Content-Types not included in the content_type_allowlist will be allowed.
In addition, by setting the Content-Type configured by the attacker at the time of file delivery, it is possible to cause XSS on the user's browser when the uploaded file is opened.
Patches
Upgrade to 3.0.5 or 2.2.5.
Workarounds
When validating with allowlisted_content_type? in CarrierWave::Uploader::ContentTypeAllowlist , forward match(\A) the Content-Type set in content_type_allowlist, preventing unintentional permission of text/html;image/png when you want to allow only image/png in content_type_allowlist.
References
OWASP - File Upload Cheat Sheet
Impact
CarrierWave::Uploader::ContentTypeAllowlist has a Content-Type allowlist bypass vulnerability, possibly leading to XSS.
The validation in
allowlisted_content_type?determines Content-Type permissions by performing a partial match.If the
content_typeargument ofallowlisted_content_type?is passed a value crafted by the attacker, Content-Types not included in thecontent_type_allowlistwill be allowed.In addition, by setting the Content-Type configured by the attacker at the time of file delivery, it is possible to cause XSS on the user's browser when the uploaded file is opened.
Patches
Upgrade to 3.0.5 or 2.2.5.
Workarounds
When validating with
allowlisted_content_type?in CarrierWave::Uploader::ContentTypeAllowlist , forward match(\A) the Content-Type set incontent_type_allowlist, preventing unintentional permission oftext/html;image/pngwhen you want to allow onlyimage/pngincontent_type_allowlist.References
OWASP - File Upload Cheat Sheet